Ruka and Reiko are spending some quality time with their mom friends from the neighborhood. One of them casually mentions that their son Ryuichi's penis is about the size of an old telephone receiver, which intrigues them. Furthermore, the mom friend has to go back to her parents' house and is worried about leaving Ryuichi at home. The two are determined to see Ryuichi's big dick, and agree to take care of him for a week, knowing that they'll help each other out in times of need. A few days later, that...